Plasma display panel and production method therefor

ABSTRACT

A plasma display panel capable of restricting the yellowing of a dielectric layer and the occurrence of dielectric breakdown, wherein glass constituting a dielectric layer uses glass containing a metal oxide MO 2  capable of a trivalent or tetravalent-ion formation in glass. Accordingly, even when Ag is ionized from an electrode consisting essentially of Ag to diffuse to a dielectric layer, Ag does not aggregate to be formed into a colloid with an ionized state kept. Therefore, yellowing and dielectric breakdown caused by Ag turning to colloid can be restricted.

TECHNICAL FIELD

[0001] The present invention relates to a plasma display panel used for image display for a computer or television or the like.

BACKGROUND ART

[0002] In the field of display devices used for image display, represented by CRT displays (CRT), liquid crystal displays (LCD), and plasma display panels, much has been expected in recent years of large high-definition screens such as high vision television screens.

[0003] CRTs, which are the most widely used among these display devices, are superior with regard to resolution and image quality, however are not suitable as devices for large screens of 40 inches or more due to their weight and depth. On the other hand, although LCDs have superior properties of low power consumption, and low driving voltage, the production of large screen LCDs is difficult, and LCDs have limited viewing angles. Compared with these devices, as well as PDPs having a wide viewing angle range, the production of large screen PDPs with shallow depth is relatively simple, and developments have already been made in 40 inch class products (for example, Kinouzairyou (Function & Materials) February 1996, volume 16, page 27).

[0004] A PDP is a type of gas discharge panel, and generally has a construction in which a front glass substrate and a back glass substrate are arranged facing each other via barrier ribs.

[0005] A plurality of conductive metal electrodes made of Ag and Cr/Cu/Cr and the like are arranged in parallel lines on the surface of the front glass substrate which faces the back substrate, and a dielectric layer which covers and insulates the metal electrodes, is formed, which is then covered with a protective layer made of MgO or the like. Also, on the surface of the back glass substrate which faces the front substrate, a plurality of metal electrodes are arranged in parallel lines, a dielectric layer is formed covering the electrodes, and, further, as well as barrier ribs being aligned on the dielectric layer, phosphor layers are applied onto the dielectric layer between the barrier ribs. A discharge gas, which includes rare gas or the like, is enclosed between the front glass substrate and the back glass substrate. When driving the PDP, ultraviolet light is emitted by the enclosed discharge gas as a result of applying a pulse voltage to the pairs of electrodes formed on the front glass substrate, and the ultraviolet light causes the phosphor layers provided on the back glass substrate to excite and irradiate. The light irradiated from the phosphor layers passes through the dielectric layer and the front glass substrate and the like, and is visible to a user. Here, the dielectric layer formed on the front glass substrate is generally constructed from glass having a low fusion point, the properties of such glass including high transparency, a baking temperature of 500-600° C., and sufficient voltage resistance.

[0006] Conventionally, Pbo or Bi₂O₃ glasses which have sufficient voltage resistance have been used as dielectric layers. However, as the relative permittivities of these glasses were high at 10-12, there was a tendency for a large amount of current to flow during discharge, and subsequently power consumption of the PDP tended to increase.

[0007] Therefore, the use of SiO₂, which has a comparatively low relative permittivity, as the dielectric layer was considered. However, because an SiO₂ film is formed by an evaporating method or a spattering method, as well as forming the film to the required thickness (20-30 μm) being difficult, the formed film was easily cracked, as it was difficult to insure a sufficient pressure resistance.

[0008] Meanwhile, Na₂O—B₂O₃—SiO₂ glasses and Na₂O—B₂O₃—ZnO glasses which do not include the abovementioned PbO, Bi₂O₃ and the like, and have relative permittivities which are lower than for conventional glass, and softening points of 500-600° C. are being developed for use as the dielectric layer (for example, as mentioned in Japanese Laid-Open Patent Publication No. 9-199037 and Laid Open Patent Publication No. 9-278482). These glasses include alkali metal oxide components such as Na₂O (sodium oxide), K₂O (potassium oxide), Li₂O (lithium oxide) to lower the glass softening point, and because the glass softening point is lowered due to the inclusion of such components, baking of the dielectric layer can be performed at a comparatively low temperature.

[0009] However, when this kind of glass, which includes a component which lowers the softening point, is used in a dielectric layer there is a possibility that yellowing will occur on the dielectric layer, front glass substrate and the like. The mechanism which causes such yellowing is considered as follows.

[0010] Display electrodes provided on the front glass substrate are made using Ag, Cu or the like, and there are cases where, at the time of baking which is performed to form the dielectric layer, Ag, Cu or the like ionizes and starts to melt and diffuse into the dielectric layer, the front glass substrate and the like. The diffused Ag and Cu ions, which are easily deoxidized by alkali metal ions such as Na ions which are ionized by the component which lowers the softening point, and Sn ions (valency 2) which are included in the front glass substrate, become colloid in such a case. When Ag and Cu have become colloid, the dielectric layer and the front glass are stained yellow or brown, that is to say, yellowing occurs (for example, J. E. SHELBY and J. VITKO Jr Journal of Non Crystalline Solides vol 50 (1982) 107-117). In PDP, because such stained glass absorbs light with a wavelength of 400 nm, problems such as decreased blue color brightness and deterioration in chromaticity occur. Further, as Ag and Cu colloids and the like are conductive, they reduce the dielectric resistance of the dielectric layer, and as the colloids are formed from deposits of colloid particles which are far larger than ions, the Ag and Cu colloids are the cause of a reflection of light which should pass through the dielectric layer, which consequently reduces PDP brightness.

[0011] In order to restrict this kind of reduction in dielectric resistance and yellowing of the dielectric layer, a possible method is to construct a double-layered dielectric layer by using PbO glass, which does not include a component which lowers the softening point of the glass, to encase the parts of the dielectric layer which are in direct contact with the display electrodes, and then laminate the PbO glass with low-permittivity Na₂O—B₂O₃—SiO₂ glass. However this method is not desirable as it increases the number of construction processes for the dielectric layer, therefore increasing construction cost. Further, from an environmental conservation viewpoint, there is also a demand for a construction method which does not use lead (Pb).

[0012] In view of the abovementioned problems, the object of the present invention is to provide a highly reliable plasma display panel that includes a dielectric layer which, in order to lower permittivity, does not include PbO, and in which yellowing of the front glass substrate, the dielectric layer and the like is restricted, and dielectric breakdown does not occur; and a production method for the PDP.

DISCLOSURE OF THE INVENTION

[0013] In order to achieve the abovementioned aims, the plasma display panel of the present invention comprises metal electrodes and a dielectric layer which covers the metal electrodes, the dielectric layer being composed of glass formed from zinc oxide, boron oxide, silicon oxide, R₂O and MO₂, wherein

[0014] the R₂O is one material selected from a group consisting of lithium oxide, sodium oxide, potassium oxide, rubidium oxide, cesium oxide, copper oxide and silver oxide, and MO₂ is one or more materials selected from the group consisting of manganese (IV) oxide, cerium (IV) oxide, tin (IV) oxide, and antimony (IV) oxide.

[0015] With this choice of materials, even when silver and copper, which are generally used for metal electrons, have ionized and diffused into the dielectric layer and front glass substrate, they can be maintained in their ionized states. Accordingly, because the aggregation of the silver and copper to form a colloid state can be restricted, the yellowing of the dielectric layer and front glass substrate, as well as dielectric breakdown, which are caused by the formation of the colloid, can be restricted.

[0016] Here, the use of alkali metal oxide R₂O can improve the pressure resistance of the dielectric layer as well as lower the softening point of the glass. Due to the addition of the alkali metal oxide R₂O to the glass, because the surface tension of the glass is lowered and fluidity is increased when the glass is melted, the pressure resistance of the dielectric layer is increased, and the incidence of pinholes and cracks in the dielectric layer is restricted. However, the alkali metal oxide R₂O, which is a component that lowers the melting-point of the glass, also accelerates yellowing, and causes yellowing to intensify when the amount of R₂O included in the glass exceeds 10% by weight, therefore it is preferable to limit the amount of R₂O to 10% by weight or less.

[0017] However, when using a glass with a composition which has 10% by weight or less of R₂O, if MO₂ is not included in the composition, although yellowing of the dielectric layer will not be noticeably visible (a b* value, which shows the yellowing of glass, is approximately 5), yellowing does actually occur, and color temperature in the PDP is significantly lowered, leading to reduction in display image quality.

[0018] Therefore, by using a glass which also includes MO₂ for the dielectric layer, the occurrence of yellowing can be restricted, while maintaining high pressure resistance and restricting dielectric breakdown.

[0019] Accordingly, a plasma display panel and production method therefor, including a highly reliable dielectric layer that is capable of restricting yellowing of the front glass substrate and the dielectric layer itself, in which dielectric breakdown does not occur, wherein the dielectric layer is made up of P₂O₅ glass or ZnO glass which includes an alkali metal oxide (R₂O) to increase pressure-resistance, and does not include PbO, B₂iO₃ and the like which lower permittivity, can be provided.

[0020] Further, it is confirmed that the occurrence of yellowing and dielectric breakdown in PDP can be restricted if the specific composition ratio of the glass which constructs the dielectric layer is zinc oxide: 35-44% by weight, boron oxide: 35-55% by weight, silicon oxide: 5-15% by weight, R₂O: 1-5% by weight, and MO₂: 0.5%-10% by weight.

[0021] Further, a glass that further includes aluminum oxide can be used for the dielectric layer. The inclusion of aluminum oxide in the glass functions to restrict the occurrence of split-phase in the dielectric layer.

[0022] Specifically, it is confirmed that the occurrence of yellowing and dielectric breakdown in PDP can be restricted when the composition ratio of the glass which constructs the dielectric layer is zinc oxide: 20-43% by weight, boron oxide: 38-55% by weight, silicon oxide: 5-17% by weight, aluminum oxide: 1-10% by weight, R₂O: 1-5% by weight, and MO₂: 0.2%-5% by weight.

[0023] Further, a glass which further includes phosphorus oxide (V) can be used for the dielectric layer.

[0024] Specifically, the occurrence of yellowing and dielectric breakdown in PDP can be restricted when the composition ratio of the glass of the dielectric layer is zinc oxide: 20-35% by weight, boron oxide: 30-55% by weight, silicon oxide: 5-12% by weight, phosphorus oxide (V): 15-25% by weight, R₂O: 0.1-5% by weight, and MO₂: 0.5-10% by weight.

[0025] Further, it is confirmed that the occurrence of yellowing and dielectric breakdown in PDP can be restricted when R₂O is potassium oxide, and the composition ratio of the glass which constructs the dielectric layer is zinc oxide: 10-25.5% by weight, boron oxide: 20-40% by weight, silicon oxide: 10-30% by weight, aluminum oxide: 5-25% by weight, potassium oxide: 3-10% by weight, and MO₂: 0.5-5% by weight.

[0026] Further, the occurrence of yellowing and dielectric breakdown in PDP can be restricted when R₂O is lithium oxide, and the composition ratio of the glass which constructs the dielectric layer is zinc oxide: 10-19% by weight, boron oxide: 20-40% by weight, silicon oxide: 10-30% by weight, aluminum oxide: 5-25% by weight, lithium oxide: 3-10% by weight, and MO₂: 1-5% by weight.

[0027] Further, the dielectric layer can be constructed from a ZnO— B₂O₃—SiO₂— Al₂O₃—R₂O glass, a P₂O₅— ZnO— B₂O₃—SiO₂—R₂O glass, or a ZnO— B₂O₃—SiO₂— MO—R₂O glass, (M is one or more materials selected from the group consisting of Mg, Ca, Sr, and Ba) which includes 0.5-5% by weight of the metal oxide MO₂ capable of trivalent or tetravalent ion configuration in glass, no more than 10% by weight of the alkali metal oxide R₂₀, and does not include PbO or B₂O₃ (R₂₀: R is one material selected from the group consisting of Li, K, Na, Cu, Ag, Cs, and Rb).

[0028] In particular, the use of silver electrodes, or chrome/copper/chrome electrodes as the metal electrodes is highly effective for the prevention of yellowing and the restriction of dielectric breakdown.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is a perspective drawing of a relevant part of a PDP;

[0030]FIG. 2 is a side cross-sectional drawing of the PDP of FIG. 1 viewed along an x axis;

[0031]FIG. 3 is a side cross-sectional drawing of the PDP of FIG. 1 viewed along a y axis;

[0032]FIGS. 4A to 4H are side cross-sectional drawings of the front panel in each production process; and

[0033]FIG. 5 is an outline sketch of an ink jet apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

[0034] One embodiment of the PDP of the present invention is explained below with reference to the drawings. The aim of the preferred embodiment, and the drawings of the invention of the present application which are shown below, is to show examples, and the present invention is not limited to these.

[0035] (Construction of PDP)

[0036] First, the construction of PDP will be explained.

[0037]FIG. 1 is a perspective drawing of a part of the (AC) PDP of the present embodiment, FIG. 2 is a cross-sectional drawing of the PDP of FIG. 1 viewed along an x axis, and FIG. 3 is a cross-sectional drawing of the PDP of FIG. 1 viewed along a y axis.

[0038] As shown in FIG. 1, the PDP has a construction which includes a front panel 10, a back panel 20, and a front glass substrate 11 in the front panel 10, and a back glass substrate 21 in the back panel 20 which are arranged parallel to each other by barrier ribs 24 and the like. The periphery of the substrates 11, 12 are sealed together by flit glass (not shown in the drawing) or the like.

[0039] As shown in FIG. 1 and FIG. 3, a scan electrode 12 a and a sustain electrode 12 b are formed parallel to each other on the surface of the front panel 10 that faces the back panel, a dielectric layer 13 which covers the electrodes 12 a and 12 b is applied to the front panel 10, and a protective layer 14 covers the dielectric layer 13. FIG. 1 and FIG. 3 illustrate only one pair of electrodes, consisting of the scanning electrode 12 a and the sustaining electrode 12 b, however there are actually a plurality of pairs of scanning electrodes 12 a and sustaining electrodes 12 b provided on the front panel 10.

[0040] The front glass substrate 11 is made of sodium borosilicate glass formed using a float method.

[0041] As shown in FIG. 3, the scan electrode 12 a and sustain electrode 12 b are made up of transparent electrodes 12 a 1 and 12 b 1 respectively, which are made of ITO, SnO2 or the like, and part of each of the electrodes 12 a 1 and 12 a 2 are laminated with metal electrodes 12 a 2 and 12 b 2 respectively, which are made of Ag or Cr/Cu/Cr, or the like and serve the function of a bus line. Here, the scan electrode 12 a and sustain electrode 12 b include the transparent electrodes 12 a 1 and 12 b 1, however a construction may be used where each of the electrodes 12 a and 12 b are made only of metal electrodes 12 a 2 and 12 b 2, without transparent electrodes.

[0042] The dielectric layer 13 is a layer of dielectric glass having a 15-40 μm film thickness, and has a function of insulating both the scan electrode 12 a and the sustain electrode 12 b.

[0043] The protective layer 14 is a layer made of magnesium oxide (MgO), and has a function of protecting the dielectric layer 13 from sputtering due to discharge which occurs during PDP driving.

[0044] The back panel 20, as shown in FIG. 1 and FIG. 2, includes the back glass substrate 21, address electrodes 22 arranged in a stripe formation onto the back glass substrate, the dielectric layer 23 which covers the address electrodes 22, barrier ribs 24 which are arranged parallel to the address electrodes 22 on the dielectric layer 23, and phosphor layers 25 of colors red, green and blue which the dielectric layer is coated in each of the spaces between the barrier ribs 24.

[0045] In the gap between the front glass substrate 11 and the back glass substrate 21, a discharge space 30 is formed which is divided up into 100-200 μm intervals by the barrier ribs 24, and this is where discharge gas made up of Ne—Xe and the like is enclosed.

[0046] When driving the PDP, by applying a voltage which is no less than a gas discharge initialization voltage to both the scan electrode 12 a on the front panel 10, and the address electrodes 22 on the back panel 20, discharge is caused near the surface of the protective layer 14 of the front panel 10. Here, the gas discharge initialization voltage varies according to the distance between the scan electrode 12 a and the address electrodes 22, the type and pressure of discharge gas, and the thickness of the dielectric layers 13 and 23 and the protective layer 14. When discharge occurs near the surface of the protective layer 14, positive ions and electrons and the like are generated by ionization, and the generated positive ions, electrons and the like move towards both the scan electrode 12 a and the sustain electrode 12 b which have poles and anti-poles. This causes the surface of the protective layer 14, made of MgO which has high resistance, to be electrically charged, however because the resistance of the MgO layer is high, the charge does not decrease, and what can be called a barrier charge forms on the protective layer 14. Because both the voltage to be applied to the scan electrode and sustain electrode, and an electric field with a negative polarity are created within the discharge space by the barrier charge, the electric field in the discharge space is weakened and the discharge soon stops.

[0047] Next, discharge is started and sustained by applying a discharge sustaining pulse to both the scan electrode 12 a and the sustain electrode 12 b. Here, because discharge occurs easily in the discharge space due to the barrier charge, the voltage of the discharge sustain pulse may be a voltage equal to or less than the gas discharge initialization voltage. Discharge of gas is intermittently sustained by the application of the abovementioned discharge sustain pulses, and ultra-violet light is generated from the discharged gas. The ultra-violet light excites the phosphor layer 25 of the back panel 20, causing the phosphor layer to emit light, the emitted light penetrates front panel 10, and an image is displayed by the PDP.

[0048] (Composition of the Dielectric Layer 13)

[0049] The characteristic point of the present invention is the discovery of a dielectric layer composition with which yellowing of the front glass substrate and the dielectric layer 13 can be restricted.

[0050] For instance, ZnO— B₂O₃—SiO₂— Al₂O₃—R₂O— MO₂ dielectric glass, ZnO— B₂O₃—SiO₂—R₂O— MO₂ dielectric glass, P₂O₅— ZnO— B₂O₃—SiO₂—R₂O— MO₂ dielectric glass, and ZnO— B₂O₃—SiO₂—CuO—R₂₀-MO₂ dielectric glass can be given as examples of dielectric glasses which are used as the dielectric layer 13. MO₂, which is included in each of the above glasses, is one or more materials selected from a group consisting of MnO₂, CeO₂, SnO₂, and SbO₂, and R₂O is one material selected from a group consisting of Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, Cu₂O, and Ag₂O.

[0051] These dielectric glasses include the oxide MO₂ of the metal M (M is one or more materials selected from the group consisting of Mn, Ce, Sn, and Sb), which is capable of trivalent or tetravalent ion configuration in glass.

[0052] Here, if the metal oxide MO₂ which is capable of trivalent or tetravalent ion configuration is included in the dielectric glass, even once Ag ions and Cu ions from the scan electrode 12 a and the sustain electrode 12 b are diffused and deoxidized in the dielectric layer, the trivalent and tetravalent metal ions are able to return Ag⁺ and Cu²⁺ to their ion state by taking Ag and Cu electrons from the deoxidized Ag and Cu, because the trivalent and tetravalent metal ions are deoxidized by the divalent metal ions. Therefore, it is considered that in the dielectric layer 13, Ag and Cu are kept in an ionized state, and colloid aggregation of Ag and Cu which have diffused from electrodes 12 a and 12 b, is restricted. As a result of this, as well as yellowing of the dielectric layer 13 being restricted, dielectric breakdown does not occur. Furthermore, because it is considered that the metal oxide included in the dielectric layer 13 usually also diffuses into the front glass substrate 11 to which the dielectric layer is applied, the occurrence of yellowing is also restricted in the front glass substrate 11.

[0053] As a specific composition, for a ZnO— B₂O₃—SiO₂— Al₂O₃—R₂O— MO₂ dielectric glass, a mixture having ZnO 20-43% by weight, B₂O₃ 38-55% by weight, SiO₂ 5-17% by weight, Al₂O₃ 1-10% by weight, R₂O 1-5% by weight, and MO₂ 0.5-5% by weight can be used.

[0054] Or, for a ZnO— B₂O₃—SiO₂—R₂O— MO₂ dielectric glass, a mixture having ZnO 35-44% by weight, B₂O₃ 35-55% by weight, SiO₂ 5-15% by weight, R₂O 1-5% by weight, and MO₂ 0.5-10% by weight can be used.

[0055] For a P₂O₅— ZnO— B₂O₃—SiO₂—R₂O— MO₂ dielectric glass, a mixture having P₂O₅ 15-25% by weight, ZnO 20-35% by weight, B₂O₃ 30-55% by weight, SiO₂ 5-12% by weight, R₂O 0.1-5% by weight, and MO₂ 0.5-10% by weight can be used.

[0056] For a ZnO— B₂O₃—SiO₂—CuO—R₂O— MO₂ dielectric glass, a mixture having ZnO 35-45% by weight, B₂O₃ 20-35% by weight, SiO₂ 5-20% by weight, CuO 0.1-5% by weight, R₂O 0.1-5% by weight, and MO₂ 0.5-10% by weight can be used.

[0057] Here, ZnO has a function of lowering the thermal expansion coefficient without significantly raising the glass softening point. B₂O₃, the main component in the glass, also has a function of lowering the glass softening point, and when the B₂O₃ content exceeds 55% by weight, the glass split-phases and the transparency of the glass is easily reduced. SiO₂ is essential to glass construction, glass formation being difficult when the SiO₂ content is less than 5% by weight, and the glass softening point being too high when SiO₂ content exceeds 20% by weight. Al₂O₃ has a property of restricting the split-phasing of glass, and when the Al₂O₃ content exceeds 10% by weight, crystallization occurs in the glass, lowering the glass transparency. R₂O has properties of lowering the glass softening point and improving the glass fluidity during melting, and, because the glass pressure resistance decreases and the thermal expansion coefficient increases when the R₂O content exceeds 10% by weight, an R₂O content in a range of 1-5% by weight is preferable. MO₂ has a property of preventing panel yellowing, and MO₂ content of 0.5%-10% by weight is preferable. This is preferable because when MO₂ content is less than 0.5% it is unable to prevent yellowing, and when MO₂ content exceeds 10%, the glass is stained.

[0058] Dielectric glass which has each of the above compositions has a permittivity of 6-7 which is low when compared with lead oxide (PbO) glass, bismuth oxide (Bi₂O₃) glass and the like (which have permittivities in a range of 10-13). Therefore, by using the dielectric glass having the above compositions as a PDP dielectric layer, the amount of electric current flowing at the driving time can be reduced, thus power consumption can be restricted. Also, because a metal oxide MO₂ which is capable of trivalent or tetravalent ion configuration is included in the dielectric layer, yellowing of the panel can be restricted. Further, as well as including R₂O which restricts the incidence of pin holes and cracks in the dielectric layer, MO₂, which can restrict colloid formation of the dielectrics silver and copper in the dielectric layer, is included, so dielectric breakdown will not occur. Dielectric breakdown is considered not to occur in both the front panel 10 and the back panel 20, because the dielectric layer 23 of the back panel 20 uses dielectric glass of the same composition as the dielectric layer in the front panel. Further, including R₂O in the ZnO glass of the present application rather than in conventional PbO glass is confirmed to be remarkably effective in improving the pressure resistance of the dielectric layer.

[0059] Furthermore, it is considered that an effect similar to that in the present embodiment can be achieved for the same reasons as above, even when the metal oxide MO₂, which is capable of trivalent or tetravalent ion configuration is combined with a ZnO— B₂O₃—SiO₂— Al₂O₃—R₂O glass, a P₂O₅— ZnO— B₂O₃—SiO₂—R₂O glass, or a ZnO-B₂O₃—SiO₂-MO-R₂O glass, which does not contain PbO or Bi₂O₃, and has no greater than 10% R₂O alkali metal oxide content, (R₂₀: R being one of Li, K, Na, Cu, Ag, Cs, and Rb), (with the condition that M is one of, or at least 2 of Mg, Ca, Sr, and Ba). In this case, the preferable amount of MO₂ added to the glass is in a range of 0.5-5% by weight. This is preferable because when the MO₂ content is less than 0.5% by weight, it is not effective in restricting yellowing, however when MO₂ content exceeds 5% by weight, the glass is stained.

[0060] (Production Method of PDP)

[0061] <Formation of the Front Panel 10>

[0062] The front panel 10 is formed by a process of forming the scan electrodes 12 a and the sustain electrodes 12 b on the front glass substrate 11, then covering the front glass substrate and formed electrodes with the dielectric layer 13 using dielectric glass powder having the abovementioned composition, and covering the dielectric layer with the protective layer 14.

[0063] (1) Formation of Scan Electrodes 12 a and Sustain Electrodes 12 b

[0064] A formation method for the scan electrodes 12 a and the sustain electrodes 12 b will be explained using FIGS. 4A to 4H.

[0065]FIG. 4A-FIG. 4H are cross-sectional drawings of the front glass substrate 11 during each process of the formation of the scan electrodes 12 a and the sustain electrodes 12 b on the glass substrate 11.

[0066] First, as is shown in FIG. 4A, the front glass substrate 11 is prepared.

[0067] Next, as is shown in FIG. 4B, one surface of the front glass substrate 11 is covered with a film of ITO (a transparent dielectric consisting of indium oxide and tin oxide) using a sputtering method, until the film thickness reaches 0.12 μm.

[0068] Next, as shown in FIG. 4C, a photoresistant layer is formed on the ITO film. Then, as shown in FIG. 4D, the photoresistant layer 121 is covered using a mask 122 that has holes 122 a, which are the same shape as the electrodes, and exposed to light. Due to this exposure, the parts of the photoresistant layer 121 corresponding to the holes 122 a of the mask 122 solidify, though the other parts of the photoresistant layer are unchanged. Then, by developing the photoresistant layer in a developing fluid, the unsolidified parts of the photoresistant layer and are washed away. After that, as shown in FIG. 4E, by performing sandblasting and etching, the parts of the ITO film which are washed away are removed, and each of the transparent electrodes 12 a 2 and 12 b 2 are formed on the scan electrodes 12 a and sustain electrodes 12 b respectively. Note that the distance between transparent electrodes 12 a and transparent electrodes 12 b is 0.08 mm so as to suit a 40-inch class PDP. Also, as an alternative to forming transparent electrodes using a photolithograph method such as used here, electrodes can be formed using a laser processing method.

[0069] Next, after a photosensitive silver paste has been appplied onto the front surface of the transparent electrodes, Ag bus line electrodes with 40 μm width are formed using the photolithograph method which is described above. Then, as shown in FIG. 4F, scan electrodes 12 a and sustain electrodes 12 b are formed by baking at a temperature of approximately 550° C.

[0070] (2) Formation of Dielectric Layer 13 and Protective Layer 14

[0071] Next, as shown in FIG. 4G, a dielectric glass paste is applied onto the front glass substrate 11 on which electrodes 12 a and 12 b are formed.

[0072] The dielectric glass paste is formed as follows.

[0073] First, dielectric glass having the previously mentioned composition is crushed using a jet mill so that the average particle size is 0.5-2.5 μm, to form dielectric glass powder. Next, a solution including the dielectric glass powder 35%-70% by weight, ethyl cellulose, ethylene oxide resin or acrylic resin 1-20% by weight, and, as a binder, turpineol, butyl carbitol acetate, or pentanediol 30-65% by weight is formed and mixed using a tripodal roll or a homonizer. By adding 0.1-10% by weight, relative to the binder, of dioctyl phthalate, dibutyl phthalate, or glycerine to the mixture as a plasticizer, and glycerol mono oleate, sorbitan sesquioleate or homogenol (produced by Kao Corporation) or the like, to the mixture as a dispersant, sedimentation of the glass powder within the paste can be prevented.

[0074] After drying the dielectric glass paste which has been applied as describe above, by baking the paste at a temperature of 500-600° C., as well as the organic components such as the binder components being dissolved, the dielectric glass powder is softened and dissolved. By cooling the baked mixture, the dielectric layer 13 is formed.

[0075] Next, the protective layer 14 made of magnesium oxide is formed on the surface of the dielectric layer 13. In the present embodiment, the protective layer 14 (thickness 1.0 μm), which is made of highly sputter-resistant MgO having (100) face or (110) face orientation, is formed using a CVD method (such as thermal CVD method or plasma CVD method). Further, instead of a CVD method, an ion plating method or vacuum evaporation method can also be used.

[0076] <Construction of the Back Panel 20>

[0077] First, the address electrodes 22 are formed on the back glass substrate 21 using a lift off method. Specifically, after the surface of the back glass substrate 21 is covered with the photoresistant layer, and the photoresistant layer has been solidified using the mask which covers the parts of the back glass substrate 11 on which address electrodes 22 are to be formed, indentations are formed in the parts of the photoresistant layer where address electrodes are to be formed, by developing. After silver paste is applied onto the whole surface of the photoresistant layer and solidified, the photoresistant layer is stripped from the back glass substrate 11. By this process, the address electrodes 22 are formed on parts of the back glass substrate 11 which correspond to the indentations in the photoresistant layer.

[0078] The dielectric layer 23 is formed on the back glass substrate 21 on which address electrodes 22 are formed, using the same method as for the dielectric layer 13 of the front panel 10 (baking at a temperature of 540-600° C.). The dielectric glass paste used in forming the dielectric layer 23 uses the same composition as the dielectric glass paste used in forming the dielectric layer 13 of the front panel 10 (excepting that the average particle size of the dielectric glass powder is 0.2-2.5 μm), with 10% by weight of white colored titanium oxide TiO₂ having an average particle size of 0.1-0.5 μm added to the composition.

[0079] Then, the barrier ribs 24 are formed on the dielectric layer 23 using a screen printing method or a plasma thermal spraying method, so as to have a predetermined pitch (for instance 0.2 mm as a suitable pitch for a 40 inch class PDP). Then, between the barrier ribs 24, phosphor inks of each of the colors red (R), green (G), and blue (B) are applied in the stated order, using a method such as an inkjet method.

[0080] Phosphors used in conventional PDPs such as Y₂O₃:Eu³⁺, Zn₂SiO₄:Mn, and BaMgAl₁₀O₁₇:Eu²⁺ can be used respectively as the red phosphor, green phosphor and blue phosphor used for the phosphor ink.

[0081]FIG. 5 is a schematic drawing showing an inkjet apparatus 70.

[0082] As shown in the drawing, the inkjet apparatus includes a server 71 which holds a reserve of phosphor ink paste, a compression pump 72 which applies pressure to the phosphor ink supplied by the server 72, and sends the phosphor ink to a nozzle 73, and the nozzle 73 which emits a jet of the phosphor ink paste sent by the compression pump 72.

[0083] When phosphor ink paste such as red phosphor ink paste is to be applied to the back panel 20 between barrier ribs 24, first a liquid mixture consisting of Y₂O₃:Eu³⁺ powder which is the red phosphor within the server 71 (average particle size 2.0 μm) 50% by weight, ethyl cellulose 1% by weight, and a solution which is a liquid mixture of α-turpineol and butyl carbitol 49% by weight is mixed using a sandmill. By this process, a phosphor ink paste having a viscosity of 55 centipoise (CP) is formed. The inkjet apparatus applies pressure to the phosphor ink paste using the pump 72 and sends the paste to the nozzle 73. A jet of the phosphor ink paste sent to the nozzle 73 (60 μm gauge nozzle) is emitted from a nozzle hole 73 a. The emitted red phosphor ink paste 74 is applied to the back panel between the barrier ribs 24. During this application, while moving the whole back panel in the lengthwise direction of the barrier ribs, the red phosphor ink paste 74 is applied by the nozzle 73, in a straight line between two adjacent barrier ribs 24. The green and blue phosphor ink pastes can be applied using the same method in which the red phosphor ink paste has been applied, however changing the types of phosphors used. After baking the back panel 20 after red, green and blue color phosphor ink pastes have been applied, at a temperature of 500° C. for 10 minutes, the back panel 20 is formed.

[0084] <Binding of Front Panel 10 to Back Panel 20>

[0085] After the front panel 10 and the back panel 20 which are formed as described above are positioned facing each other, the peripheries of both panels are sealed together using sealing glass. Here, the discharge space which is between barrier ribs 24 is evacuated to create a vacuum (1×10⁻⁴ Pa), and then discharge gas is enclosed in the discharge space with a predetermined pressure, thereby forming the PDP. Here, a conventionally-used Ne—Xe gas is used as the discharge gas, however by using a gas having no less than 5% per volume Xe content with a discharge gas pressure of 66.5-100 kPa, the brightness of the PDP can be improved.

[0086] (Experiments)

[0087] Next, experiment samples 1-36 of the PDP of the above preferred embodiment, and comparative samples 37-40 were produced, and a comparative investigation of front panel color, brightness, color temperature and the like was performed.

[0088] A 42 inch VGA type PDP (having 480 pairs of scan electrodes and sustain electrodes, and 2556 address electrodes) was produced as the PDP for each experiment sample and comparative sample. As the PDP cell size, the height of the barrier ribs was 0.15 mm, the interval between the barrier ribs (cell pitch) was 0.36 mm, and the distance between the display electrodes and sustain electrodes was 0.08 mm. Here, transparent electrodes with silver electrodes attatched as bus electrodes were used as display electrodes and sustain electrodes, and silver electrodes were used as address electrodes.

[0089] The dielectric layers of both the front panel and the back panel were made of dielectric glass including one or more metal oxides capable of tetravalent ion configuration, as explained in the preferred embodiment. A glass powder having an average particle size of 0.5-2.5 μm was used as the dielectric glass powder in the formation of the dielectric layer, and mixed with a solvent, a plasticizer, and a dispersant to form a dielectric glass paste (20000-50000 centipoise), and the dielectric glass paste was applied using a dyecoat method and baked to form each dielectric layer. The dielectric layers were formed with 25˜30 μm thickness. Further, a paste which combined titanium oxide with paste having the same composition as the paste used for the formation of the front panel dielectric layer, was used for the formation of the back panel dielectric layer.

[0090] A Ne—Xe gas mixture (Xe content 5% per volume) was used as a discharge gas and enclosed at a pressure of 79.8 kPa (600 torr).

[0091] The protective layer for the front panel was formed using a plasma CVD method, with Magnesium Acetylacetone [Mg (C₅H₇O₂)₂] or Magnesium Dipivaloyl Methane [Mg (C₁₁H₁₉O₂) 2] as a source. In the plasma CVD method, the method used for forming the protective layer was one of, with a vaporizer temperature set at 125° C., and the front panel heating temperature set at 250° C., applying the magnesium source with 300 W of a 13.56 MHz high frequency electric field from a high frequency power source, per period of 20 seconds, while supplying Ar gas and oxygen onto the front panel at rates of 1 L per minute and 2 L per minute respectively, while reducing the pressure to 1.33 kPa (10 torr) By this method, a protective layer consisting of MgO, with thickness 1.0 μm was formed with a film formation speed of 1.0 μm per minute. The protective layer formed in this way was verified by x-ray analysis to have (100) face orientation, regardless of which source was used.

[0092] (1) Experiment Samples 1-8

[0093] P₂O₅— ZnO— B₂O₃—SiO₂— MO₂—R₂O glass powder which includes a metal oxide capable of tetravalent ion configuration, and was described in the preferred embodiment, was used as the glass powder to form the dielectric layer. Table 1 shows, for each sample, the glass composition, the type of binder and the like used in the dielectric glass paste, and the baking temperature of the dielectric layer and the like. TABLE 1 Amount Baking Film of glass Amount of temper- thickness Permit- powder binder in Amount of Amount of ature of of die- tivity of in glass glass dispersant plasticizer dielectric lectric die- Trial Composition of Dielectric Glass paste paste in binder in binder glass glass lectric Number P₂O₅ ZnO B₂O₃ SiO₂ Al₂O₃ R₂O MO₂ (wt %) (wt %) (wt %) (wt %) (° C.) (μm) glass 1 10 20 50 12 — Na₂O 5 MnO₂ 3 55 Ethyl Homogenol Dibutyl 550 30 6.3 cellulose 0.2 phthalate 45 2.5 2 10 25 40 10 — K₂O 5 MnO₂ 65 Acrylic Glycerol Dibutyl 550 25 6.2 10 35 mono oleate phthalate 0.2 2.5 3 25 35 30 7.5 — Li₂O 2 SnO₂ 70 Ethylene Sorbitan Dioctyl 545 30 6.3 0.5 oxide sesquioleate phthalate 3 30 0.1 4 20 30 39.4 10 — K₂O MnO₂ 35 Ethyl Homogenol Dioctyl 565 25 6.3 0.1 0.5 cellulose 0.1 phthalate 3 65 5 20 30 30 10 — Cs₂O 5 CeO₂ 5 40 Ethyl Homogenol Glycerine 2 553 30 6.5 cellulose 0.1 60 6 20 34 30 10 — K₂O 5 CeO₂ 1 50 Acrylic Glycerol Dioctyl 560 30 6.5 50 mono oleate phthalate 0.2 1.5 7 20 30 30 10 — Rb₂O 5 SbO₂ 5 65 Acrylic Homogenol — 554 30 6.3 35 0.1 8 20 30 30 14.5 — Ag₂O 5 SbO₂ 65 Acrylic Homogenol — 559 25 6.5 0.5 35 0.1

[0094] (2) Experiment Samples 9-16

[0095] ZnO-B₂O₃—SiO₂-MO₂—R₂O glass powder, which includes a metal oxide capable of tetravalent ion configuration, and was described in the preferred embodiment, was used as the glass powder to form the dielectric layer. Table 2 shows, for each sample, the glass composition, the type of binder and the like used in the dielectric glass paste, and the baking temperature of the dielectric layer and the like. TABLE 2 Amount Baking Film of glass Amount of temper- thickness Permit- powder binder in Amount of Amount of ature of of die- tivity of in glass glass dispersant plasticizer dielectric lectric die- Trial Composition of Dielectric Glass paste paste in binder in binder glass glass lectric Number P₂O₅ ZnO B₂O₃ SiO₂ Al₂O₃ R₂O MO₂ (wt %) (wt %) (wt %) (wt %) (° C.) (μm) glass  9 — 25 55 5 — Li₂O 5 MnO₂ 55 Acrylic Homogenol Dioctyl 540 30 6.5 10 45 0.2 phthalate 2 10 — 30 40 15 — K₂O 5 CeO₂ 65 Acrylic Glycerol Dibutyl 545 25 6.5 10 35 mono oleate phthalate 3 0.2 11 — 37 42.5 15 — Na₂O 5 MnO₂ 70 Ethyl Sorbitan Dibutyl 545 25 6.5 0.5 cellulose sesquioleate phthalate 4 30 0.1 12 — 44 35 10 — Cu₂O 5 SnO₂ 6 40 Ethyl Homogenol Dibutyl 545 25 6.5 cellulose 0.2 phthalate 4 60 13 — 40 45 10 — Ag₂O 2 SbO₂ 3 45 Ethyl Homogenol Dibutyl 550 25 6.6 cellulose 0.2 phthalate 4 55 14 — 40 50 8.5 — K₂O 1 CeO₂ 45 Ethyl Homogenol Dibutyl 560 30 6.8 0.5 cellulose 0.2 phthalate 4 55 15 — 40 40 10 — Cs₂O 5 SnO₂ 5 50 Ethyl Homogenol Dibutyl 550 30 6.5 cellulose 0.2 phthalate 4 50 16 — 35 47 12.5 — Rb₂O 5 SbO₂ 50 Ethyl Homogenol Dibutyl 550 30 6.4 0.5 cellulose 0.2 phthalate 4 50

[0096] (3) Experiment Samples 17-24

[0097] ZnO—B₂O₃—SiO₂—Al₂O₃-MO₂—R₂O glass powder which includes a metal oxide capable of tetravalent ion configuration, and was described in the preferred embodiment, was used as the glass powder to form the dielectric layer. Table 3 shows, for each sample, the glass composition, the type of binders and the like used in the dielectric glass paste, and the baking temperature of the dielectric layer and the like. TABLE 3 Amount Baking Film of glass Amount of temper- thickness Permit- powder binder in Amount of Amount of ature of of die- tivity of in glass glass dispersant plasticizer dielectric lectric die- Trial Composition of Dielectric Glass paste paste in binder in binder glass glass lectric Number P₂O₅ ZnO B₂O₃ SiO₂ Al₂O₃ R₂O MO₂ (wt %) (wt %) (wt %) (wt %) (° C.) (μm) glass 17 — 32 38 15 5 Ag₂O 5 MnO₂ 5 55 Acrylic Homogenol Dibutyl 560 30 6.4 45 0.2 phthalate 2 18 — 40 40 17 1 Cu₂O 1 CeO₂ 1 65 Acrylic Homogenol Dibutyl 550 30 6.4 35 0.2 phthalate 2 19 — 20 55 12 3 Na₂O 5 SnO₂ 5 70 Ethyl Homogenol Dibutyl 555 30 6.3 cellulose 0.2 phthalate 2 30 20 — 43 40 5 10 K₂O 1 SbO₂ 1 65 Ethyl Homogenol Dibutyl 560 30 6.5 cellulose 0.2 phthalate 2 35 21 — 40 45 5 5 Cs₂O 5 MnO₂ 65 Ethyl Homogenol Dibutyl 565 30 6.5 0.5 cellulose 0.2 phthalate 2 35 22 — 40 40 9.5 5 Rb₂O 5 CeO₂ 65 Ethyl Homogenol Dibutyl 560 30 6.5 0.5 cellulose 0.2 phthalate 2 35 23 — 42 43 5 5 K₂O 5 SbO₂ 5 65 Ethyl Homogenol Dibutyl 560 30 6.5 cellulose 0.2 phthalate 2 35 24 — 32 47 6 10 Ag₂O 4 MnO₂ 1 65 Ethyl Homogenol Dibutyl 560 30 6.4 cellulose 0.2 phthalate 2 35

[0098] (4) Experiment Samples 25-32

[0099] ZnO-B₂O₃—SiO₂—Al₂O₃-MO₂—K₂O glass powder which includes a metal oxide capable of tetravalent ion configuration, and was described in the preferred embodiment, was used as the glass powder to form the dielectric layer. Table 4 shows, for each sample, the glass composition, the type of binder and the like used in the dielectric glass paste, and the baking temperature of the dielectric layer and the like. TABLE 4 Amount Baking Film of glass Amount of temper- thickness Permit- powder binder in Amount of Amount of ature of of die- tivity of in glass glass dispersant plasticizer dielectric lectric die- Trial Composition of Dielectric Glass paste paste in binder in binder glass glass lectric Number P₂O₅ ZnO B₂O₃ SiO₂ Al₂O₃ R₂O MO₂ (wt %) (wt %) (wt %) (wt %) (° C.) (μm) glass 25 — 15 20 30 20 K₂O MnO₂ 5 55 Acrylic Homogenol Dibutyl 595 30 6.7 10 45 0.2 phthalate 2 26 — 19 40 10 25 K₂O 3 CeO₂ 3 60 Ethyl Glyceryl Dibutyl 575 30 6.4 cellulose trioleate phthalate 2 40 0.2 27 — 10 35 25 20 K₂O 8 SnO₂ 2 60 Ethyl Homogenol Dibutyl 580 30 6.5 cellulose 0.2 phthalate 2 40 28 — 20 30 30 5 K₂O SbO₂ 5 60 Ethyl Homogenol Dibutyl 570 30 6.7 10 cellulose 0.2 phthalate 2 40 29 — 10.5 40 25 19 K₂O 5 MnO₂ 70 Ethyl Homogenol Dibutyl 585 30 6.7 0.5 cellulose 0.2 phthalate 2 30 30 — 25.5 30 20 20 K₂O 5 SnO₂ 70 Ethyl Homogenol Dibutyl 575 30 6.7 0.5 cellulose 0.2 phthalate 2 30 31 — 21.5 30 15 25 K₂O 8 SbO₂ 70 Ethyl Homogenol Dibutyl 575 30 6.8 0.5 cellulose 0.2 phthalate 2 30 32 — 24.5 30 15 20 K₂O CeO₂ 70 Ethyl Homogenol Dibutyl 575 30 6.7 10 0.5 cellulose 0.2 phthalate 2 30

[0100] (5) Experiment Samples 33-36

[0101] ZnO-B₂O₃—SiO₂—Al₂O₃-MO₂—Li₂O glass powder which includes a metal oxide capable of tetravalent ion configuration, and was described in the preferred embodiment, was used as the glass powder to form the dielectric layer. Table 5 shows, for each sample, the glass composition, the type of binder and the like used in the dielectric glass paste, and the baking temperature of the dielectric layer and the like. TABLE 5 Amount Baking Film of glass Amount of temper- thickness Permit- powder binder in Amount of Amount of ature of of die- tivity of in glass glass dispersant plasticizer dielectric lectric die- Trial Composition of Dielectric Glass paste paste in binder in binder glass glass lectric Number P₂O₅ ZnO B₂O₃ SiO₂ Al₂O₃ R₂O MO₂ (wt %) (wt %) (wt %) (wt %) (° C.) (μm) glass 33 — 15 20 30 20 i₂O SnO₂ 5 55 Acrylic Homogenol Dioctyl 545 30 6.5 10 45 0.2 phthalate 2 34 — 19 40 10 25 Li₂O 3 SbO₂ 3 35 Ethyl Homogenol Dibutyl 565 30 6.3 cellulose 0.1 phthalate 3 65 35 — 10 35 25 20 Li₂O 8 CeO₂ 2 65 Ethyl Homogenol Dibutyl 565 30 6.3 cellulose 0.2 phthalate 2 35 36 — 19 35 30 5 Li₂O MnO₂ 1 65 Ethyl Homogenol Dibutyl 565 30 6.3 10 cellulose 0.2 phthalate 2 35

[0102] (6) Comparative Samples 37-40

[0103] ZnO or P₂O₅ glass powder which does not include the metal oxide MO₂ (M=Mn, Ce, Sn, Sb) capable of tetravalent ion configuration which was described in the preferred embodiment, was used as the glass powder to form the dielectric layer. Table 6 shows, for each sample, the glass composition, the type of binder and the like used in the dielectric glass paste, and the baking temperature of the dielectric layer and the like. TABLE 6 Amount Baking Film of glass Amount of temper- thickness Permit- powder binder in Amount of Amount of ature of of die- tivity of in glass glass dispersant plasticizer dielectric lectric die- Trial Composition of Dielectric Glass paste paste in binder in binder glass glass lectric Number P₂O₅ ZnO B₂O₃ SiO₂ Al₂O₃ R₂O MO₂ (wt %) (wt %) (wt %) (wt %) (° C.) (μm) glass 37* — 32 43 15 5 Ag₂O 5 — 55 Acrylic Homogenol Dibutyl 590 30 6.5 45 0.2 pthalate 2 38* — 18 20 40 12 Na₂O — 60 Ethyl Homogenol Dibutyl 575 30 6.3 10 cellulose 0.2 phthalate 2 40 39* — 25 55 15 5 — — 35 Ethyl Sorbitan Dibutyl 575 30 6.6 cellulose sesquioleate phthalate 2 65 0.2 40* — 35 30 17 10 K₂O 8 — 40 Ethyl Sorbitan — 575 30 6.5 cellulose sesquioleate 60 0.2

[0104] (7) Experiments

[0105] Method of Experiments

[0106] For each of the experiment samples 1-36 and each of the comparative examples 37-40, the extent of staining of the front panel between the pair of scan electrodes and pair of sustain electrodes was determined using a colorimeter (Nippon Denshoku Industries (Co., Ltd) NF777). An a* and a b• value, which both indicate the extent of staining of the glass were items to be determined, and were determined based on the color difference display method stipulated in JISZ8730.

[0107] Further, when causing each PDP sample to display all white, as well as measuring brightness, color temperature was determined using a multi-channel spectrometer (Otsuka Electronics Co., Ltd MCPD-7000). When the PDP screen is caused to display all white, a discharge sustain pulse, with a 180 V voltage, and 50 kHz frequency, which does not usually cause dielectric breakdown, is applied to the PDP.

[0108] Further, in each of samples 1-40, the permittivity of the front panel dielectric layer is determined before the panels are sealed together. To determine permittivity, silver paste was applied to the front panel dielectric layer and dried and used as one electrode, an address electrode was used as the other electrode, and an LCR meter was used to measure permittivity between the electrodes. The determined permittivity results are given in Tables 1-6.

[0109] (8) Results and Consideration

[0110] Each determined result for experiment samples 1-8, 9-16, 17-24, 25-32, 33-36, and comparative samples 37-40 are shown in tables 7, 8, 9, 10, 11 and 12 respectively. Note that it in each table a greater a* in a positive direction shows a higher intensity of red, and a greater a* in a negative direction shows a higher intensity of green. A greater b* in a positive direction shows a higher intensity of yellow, and a greater b* in a negative direction shows a higher intensity of blue. Generally, if both a* and b• are in a range of −5-+5, no staining will be visible on the front panel. In particular, because the size of b* influences yellowing, if b• is in the range of −5-+5, yellowing will not be visible, however when b* exceeds +10, yellowing becomes noticeable. TABLE 7 Values determined by Panel color Colorimeter Panel brightness temperature Trial Number a* b* (cd/m²) (K) 1 −0.3 1.0 550 9110 2 1.2 0.8 552 9250 3 −1.5 1.8 541 9003 4 −0.8 1.2 540 9102 5 −1.3 1.0 542 9125 6 −1.5 1.3 547 9085 7 −1.2 1.4 537 9050 8 −1.8 2.0 540 8900

[0111] TABLE 8 Values determined by Panel color Colorimeter Panel brightness temperature Trial Number a* b* (cd/m²) (K) 9 −0.2 0.5 560 9326 10 −1.8 1.3 554 9015 11 −1 1.2 545 9102 12 −1.9 1.0 538 9118 13 −1.5 1.2 540 9108 14 −1.8 1.6 552 9062 15 −1.3 1.2 548 9125 16 −1.7 2.0 545 8950

[0112] TABLE 9 Values determined by Panel color Colorimeter Panel brightness temperature Trial Number a* b* (cd/m²) (K) 17 −0.8 0.9 520 9200 18 −1.3 1.2 505 9150 19 −1.5 1.0 510 9170 20 −1.6 1.3 522 9100 21 −1.1 1.4 538 9045 22 −1.8 1.9 542 8960 23 −1.5 1.3 526 9110 24 −1.2 1.2 525 9125

[0113] TABLE 10 Values determined by Panel color Colorimeter Panel brightness temperature Trial Number a* b* (cd/m²) (K) 25 −0.5 0.6 550 9280 26 −1.3 1.5 554 9020 27 −1.6 1.7 545 9001 28 −1.4 1.3 553 9136 29 −1.2 1.4 532 9087 30 −1.8 2.0 527 8905 31 −1.9 2.0 534 8900 32 −1.7 2.0 550 8903

[0114] TABLE 11 Values determined by Panel color Colorimeter Panel brightness temperature Trial Number a* b* (cd/m²) (K) 33 −1.8 1.6 560 9001 34 −1.7 1.5 558 9053 35 −1.3 1.6 550 9047 36 −1.3 1.2 546 9125

[0115] TABLE 12 Values determined by Panel color Colorimeter Panel brightness temperature Trial Number a* b* (cd/m²) (K) 37* −1.5 5.1 500 7600 38* −1.5 6.2 495 7580 39* −1.9 6.5 498 7540 40* −2.0 7.0 496 7430

[0116] As shown in table 7, in PDPs provided with a dielectric layer consisting of P₂O₅— ZnO— B₂O₃—SiO₂— MO₂—R₂O glass which includes the metal oxide MO₂ capable of trivalent or tetravalent ion configuration, b* which indicates yellowing, is 0.8-2.0. It can be seen that b* is kept low here, in comparison with b* (5.1-7.0) in comparative samples 37-40 shown in table 12. In particular, it is verified that the problem of yellowing is clearly improved in the dielectric layer of table 7, even when comparing the experiment sample 1 and comparative sample 38, which have the same composition as each other except for the presence of MnO₂ in the dielectric layer.

[0117] Further, regarding PDP brightness, experiment samples 1-8 show a brightness of no less than 537 cd/m² which is greater than the brightness of no more than 500 cd/m² of the comparative samples 37-40. This is considered to be because the formation of colloid, which reflects light, is restricted, even if silver has diffused into the dielectric layer. In addition, in the present experiment samples 1-8, the panel color temperature is satisfactory as it is not a color temperature at which yellowing will occur.

[0118] It can also be seen that, in the PDP provided with a dielectric layer made of ZnO—B₂O₃—SiO₂-MO₂—R₂O glass, which is shown in table 8, b* which indicates yellowing is kept low in comparison with b* in the comparative samples 37-40, at 0.5-2.0. In particular, it is verified that the problem of yellowing is clearly improved in the dielectric layer of table 8, even when comparing the experiment sample 9 (b*=0.5) and comparative sample 39 (b*=6.5), which have the same composition as each other except for the presence of MnO₂ in the dielectric layer.

[0119] Further, regarding PDP brightness, experiment samples 9-16 show a higher brightness, of no less than 538 cd/m², than the brightness of no more than 500 cd/m² of the comparative samples 37-40. In addition, in the present experiment samples 9-16, the panel color temperature is preferable in comparison with that of the comparative samples 37-40.

[0120] It can also be seen that, in the PDP provided with the dielectric layer made of ZnO-B₂O₃—SiO₂—Al₂O₃-MO₂—R₂O glass, which is shown in table 9, b* which indicates yellowing is 0.9-1.9, which, similarly to the previously mentioned glass, is kept low in comparison with b* in the comparative samples 37-40. In particular, it is verified that the problem of yellowing is clearly improved in the dielectric layer of table 9, even when comparing the experiment sample 17 (b*=0.9) and experiment sample 24 (b*=1.2) with comparative sample 37 (b*=7.0) which have the same composition as each other except for the presence of MnO₂ in the dielectric layer.

[0121] Further, regarding PDP brightness, experiment samples 17-24 show a higher brightness, of no less than 510 cd/m², than the brightness of no more than 500 cd/m² of the comparative samples 37-40. In addition, in the present experiment samples 17-24, the panel color temperature is preferable in comparison with that of the comparative samples 37-40.

[0122] It can also be seen that, in the PDPs provided with the dielectric layer made of ZnO-B₂O₃—SiO₂—Al₂O₃-MO₂—K₂O glass, which is shown in table 10, b* which indicates yellowing is 0.6-2.0, which, similarly to the previously mentioned glass, is kept low in comparison with b* in the comparative samples 37-40. In particular, it is verified that the problem of yellowing is clearly improved in the dielectric layer of table 10, even when comparing the experiment samples of table 10 and comparative sample 40 (b*=7.0) which have the same composition except for the presence of MnO₂ in the dielectric layer.

[0123] Further, regarding PDP brightness, experiment samples 25-32 show a higher brightness, of no less than 527 cd/m², than the brightness of no more than 500 cd/m² of the comparative samples 37-40. In addition, in the present experiment samples 25-32, the panel color temperature is preferable in comparison with that of the comparative samples 37-40.

[0124] It can also be seen that, in the PDPs provided with the dielectric layer made of ZnO-B₂O₃—SiO₂—Al₂O₃-MO₂—Li₂O glass, which is shown in table 11, b* which indicates yellowing is 1.2-1.6, which, similarly to the previously mentioned glass, is kept low in comparison with b* in the comparative samples 37-40.

[0125] Further, regarding PDP brightness, experiment samples 33-36 show a higher brightness, of no less than 546 cd/m², than the brightness of no more than 500 cd/m² of the comparative samples 37-40. In addition, in the present experiment samples 25-32, the panel color temperature is preferable in comparison with that of the comparative samples 37-40.

INDUSTRIAL APPLICABILITY

[0126] The plasma display panel of the present invention, and production method thereof, is particularly effective for a plasma display panel provided with a dielectric layer made of glass that has a low melting point. 

1. A plasma display panel comprising metal electrodes and a dielectric layer which covers the metal electrodes, the dielectric layer being composed of glass formed from zinc oxide, boron oxide, silicon oxide, R₂O and MO₂, wherein the R₂0 is one material selected from a group consisting of lithium oxide, sodium oxide, potassium oxide, rubidium oxide, cesium oxide, copper oxide and silver oxide, and MO₂ is manganese (IV) oxide.
 2. The plasma display panel of claim 1, wherein a composition ratio of the glass is zinc oxide: 25-44% by weight, boron oxide: 35-55% by weight, silicon oxide: 5-15% by weight, R₂0: 1-5% by weight, and MO₂: 0.5%-10% by weight.
 3. The plasma display panel of claim 1 wherein the glass further includes aluminum oxide.
 4. The plasma display panel of claim 3 wherein a composition ratio of the glass is zinc oxide: 20-43% by weight, boron oxide: 38-55% by weight, silicon oxide: 5-17% by weight, aluminum oxide 1-10% by weight, R₂0: 1-5% by weight, and MO₂: 0.5%-5% by weight.
 5. The plasma display panel of claim 1 wherein the glass further includes phosphorus (V) oxide.
 6. The plasma display panel of claim 5 wherein a composition ratio of the glass is zinc oxide: 20-35% by weight, boron oxide: 30-55% by weight, silicon oxide: 5-12% by weight, phosphorus (V) oxide: 15-25%, R₂O: 0.1-5% by weight, and MO₂: 0.5-10% by weight.
 7. The plasma display panel of claim 3 wherein the R₂O is potassium oxide, and the composition ratio of the glass is zinc oxide: 10-25.5% by weight, boron oxide: 20-40% by weight, silicon oxide: 10-30% by weight, aluminum oxide: 5-25% by weight, potassium oxide: 3-10% by weight, and MO₂: 0.5-5% by weight.
 8. The plasma display panel of claim 3 wherein the R₂O is lithium oxide, and a composition ratio of the glass is zinc oxide: 10-19% by weight, boron oxide: 20-40% by weight, silicon oxide: 10-30% by weight, aluminum oxide: 5-25% by weight, lithium oxide: 3-10% by weight, and MO₂: 1-5% by weight.
 9. A plasma display panel comprising metal electrodes and a dielectric layer which covers the metal electrodes, the dielectric layer being composed from a ZnO— B₂O₃—SiO₂—Al₂O₃—R₂O glass, a P₂O₅— ZnO— B₂O₃—SiO₂—R₂O glass, or a ZnO— B₂O₃—SiO₂-MO₂—R₂O glass, the glass including 0.5-5% by weight of metal oxide MO₂ which is capable of trivalent or tetravalent ion configuration in glass, no more than 10% by weight of R₂₀, and not including PbO or B₂O₃, wherein the R₂O is one material selected from the group consisting of lithium oxide, sodium oxide, potassium oxide, rubidium oxide, cesium oxide, copper oxide and silver oxide, and MO₂ is manganese (IV) oxide.
 10. The plasma display panel of claim 1 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers.
 11. A plasma display panel production method including a process of applying dielectric glass powder onto metal electrodes and baking the applied dielectric glass powder, thereby covering the metal electrodes with a dielectric layer, the dielectric glass powder including zinc oxide, boron oxide, silicon oxide, R₂O, and MO₂, wherein the R₂O is one material selected from the group consisting of lithium oxide, sodium oxide, potassium oxide, rubidium oxide, cesium oxide, copper oxide and silver oxide, and MO₂ is manganese (IV) oxide.
 12. The plasma display panel production method of claim 11, wherein a composition of the dielectric glass powder is zinc oxide: 25-44% by weight, boron oxide: 35-55% by weight, silicon oxide: 5-15% by weight, R₂O: 1-5% by weight, and MO₂ 0.5-10% by weight.
 13. The plasma display panel production method of claim 11, wherein the dielectric glass powder further includes aluminum oxide, and a composition ratio of the dielectric glass is zinc oxide: 20-43% by weight, boron oxide: 38-55% by weight, silicon oxide: 5-17% by weight, aluminum oxide: 1-10% by weight, R₂O: 1-5% by weight, and MO₂: 0.2-5% by weight.
 14. The plasma display panel production method of claim 11, wherein the dielectric glass powder further includes phosphorus (V) oxide, and a composition ratio of the dielectric glass is zinc oxide: 20-35% by weight, boron oxide: 30-55% by weight, silicon oxide: 5-12% by weight, phosphorus (V) oxide: 15-25% by weight, R₂O: 0.1-5% by weight, and MO₂: 0.5-10% by weight.
 15. The plasma display panel of claim 2 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers.
 16. The plasma display panel of claim 3 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers.
 17. The plasma display panel of claim 4 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers.
 18. The plasma display panel of claim 5 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers.
 19. The plasma display panel of claim 6 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers.
 20. The plasma display panel of claim 7 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers.
 21. The plasma display panel of claim 8 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers.
 22. The plasma display panel of claim 9 wherein the metal electrodes are silver electrodes or electrodes formed from chrome/copper/chrome layers. 